The purpose of studies in this protocol is to compare rates of fatty acid synthesis in diets that differ in the amount and type of carbohydrate and in different subsets of the population. The extent of fatty acid synthesis is measured from changes in the relative percentages of palmitate and linoleate in plasma VLDL triglyceride and from the incorporation of intravenously infused 13C acetate in plasma VLDL palmitate. It is hypothesized that obese subjects with a predominance of abdominal fat and increased blood triglyceride will show higher rates of fatty acid synthesis than normal subjects on low fat, high sugar diets. The relation of fatty acid synthesis to blood triglyceride and insulin levels will be examined.